Steve Lewis, center, shows graduate student Rachel Wheat, left, how to place calipers to take length and depth measurements of the beak of a bald eagle captured in the Alaska Chilkat Bald Eagle Preserve.

Before dawn, Steve Lewis crosses the snowy flats around Southeast Alaska's Chilkat River. Beyond its braided channel rise the Takhinsha Mountains, obscured by fog in the murky autumn light. A handful of biologists follow Lewis -- a tall, trim 42-year-old with a close-cropped beard -- as he sloshes through riffles to a gravel bar. He builds a perch snare by tying an alder branch to an upright log and rigs it with a spring-loaded loop. "Ready for action," he whispers, hoping to conceal our presence from the Chilkat's chattering denizens.

Dozens of bald eagles, their chirps surprisingly meek, hunker in the river's bare cottonwoods. Between 3,500 and 4,000 migrate each fall to this six-mile stretch of the Chilkat Valley, called the Council Grounds, in the largest gathering of bald eagles on Earth. To protect them, Alaska designated a 48,000-acre area as the Chilkat Bald Eagle Preserve in 1982.

The eagles come here -- about 21 miles north of Haines -- to feed on spawning chum salmon. The great mystery is where they come from. Eagles migrate thousands of miles to exploit seasonal food sources, which means the new arrivals could live and breed as far away as the Rocky Mountains in the Lower 48. Also puzzling is how they know the chum emerge after other salmon runs have finished.

Lewis, a Juneau-based U.S. Fish and Wildlife Service raptor expert, and the others are here to help University of California-Santa Cruz doctoral candidate Rachel Wheat catch and outfit eagles with solar-powered GPS transmitters to find some answers.

But where Lewis and his colleagues see globally significant biological riches, Constantine Metal Resources sees a different treasure. In February, the company closed a deal to accelerate exploration of a 5-million-ton copper-zinc deposit with what it calls "tremendous expansion potential" right above the Chilkat's largest headwater tributary, three miles from the preserve.

As with any protected landscape, the resources that sustain wildlife here do not begin and end with the preserve's boundaries. Lewis and others fear that mine pollution could jeopardize this important chum run -- just as they begin to understand its role -- and the mainland eagle populations that depend on it.

On paper, the Chilkat Bald Eagle Preserve is "the most protected piece of real estate in Alaska," says former state Rep. Peter Goll, a Haines resident who fought for the preserve and helped craft its first management plans.

On the ground, it's a different story.

Like many Alaska towns, Haines' fortunes rose and fell with natural resource supplies. It boomed as gold seekers headed north to the Klondike, then to Porcupine Creek near the Constantine claim in the late 1890s. When the big mines closed in the 1930s, canneries sustained Haines until commercial overfishing forced them to fold in the early '70s. By the '80s, Haines' sawmills followed suit, leaving many of its 1,700 residents jobless.

Hoping to revive Haines' timber industry, the state opened the heart of eagle habitat to large-scale clear-cutting in 1979. National conservation groups, supported by Goll and many other locals, sued to block the timber sale. They lost the suit but won powerful allies in Congress, who floated a provision to create a national eagle refuge.

Determined to avoid federal interference, local miners and loggers, and state and town officials forged a landmark compromise with conservation groups, creating a state forest open to resource development and an eagle preserve that permitted only low-impact activities, such as subsistence fishing, hunting, research and wildlife viewing.

Ironically, the timber market never rebounded and even the eagles' most diehard foes came to see their economic potential. In 1985, local businessman Dave Olerud, who once threatened to rally opponents to kill off "those goddamned buzzards," started the Bald Eagle Foundation, which runs an annual festival that draws close to 300 tourists each November.

To a degree, Haines owes its life to the preserve, which also offers sanctuary to 300 to 400 resident eagles. As many as 15,000 people visit the area annually, sleeping, eating and shopping in locally run businesses. Tourism accounts for most jobs in Haines, but the work is seasonal: Unemployment rates last year swung from 4.7 percent at the height of tourist season in August to 12.9 in February, compared to a national high of 8.3 percent. Though most people in Haines clearly value the preserve, many also want new opportunities. A survey last year revealed that 50 percent of residents support local "larger scale mining such as the Constantine Mineral deposit in the Chilkat Valley."

The mine isn't the only development project on the horizon. On Connelly Lake, a few miles north of the Council Grounds, a proposed hydroelectric dam is moving forward. So are state plans to build a heavy-duty bridge on the Chilkat for big rigs hauling Yukon ore -- potentially making Haines the Pacific Rim's prime ore shipping site -- good news for Constantine.

More from Wildlife

If you're interested in learning more about this research program or would like to see where the GPS-tagged eagles have traveled, check out the website for the study: www.ecologyalaska.com

Kirk Hohenberger

May 28, 2013 01:46 PM

When will it end? Always more mines, more development ,more human impact, less habitat, nothing pristine,for every new mine, new gas or oil well, how about a new protected reserve , to mitigate all the "take" so we as humans do not impact everywhere .

Kirk Hohenberger

May 28, 2013 02:30 PM

Alaska is called the last Frontier. It still remains Uniquely Pristine. It has not been ruined like the lower fourty eight has.How long will it take Alaskans to rid this wilderness of the salmon, and wildness.